Gillespie landed awkwardly during a play with 6 minutes, 38 seconds remaining in the first half and immediately grabbed at his left leg. He tried to walk it off along the baseline after the play, but then he left the bench and had to be helped to the locker room.
The school announced at halftime that Gillespie was out for the game with a left knee injury.
"It's serious," Wright said when asked about the injury during his postgame interview with FS1. "We don't know exactly what it is. But it's serious."
Wright said later during his postgame news conference that Gillespie will undergo an MRI Thursday morning.
Junior wing Brandon Slater started the second half in Gillespie's place and finished with 11 points as the Wildcats locked up the Big East regular-season title.
Gillespie has been a starter for Wright's team for the past three years after playing a key role off the bench on Villanova's national championship team in 2018. He's averaging 14.4 points, 3.3 rebounds and 4.7 assists this season, shooting 37.4% from 3-point range.